Run dbus-uuidgen in Ubuntu Wily Dockerfile

Otherwise the tests will fail with:

  INVALID: process 975: D-Bus library appears to be incorrectly set up; failed to read machine uuid: UUID file '/etc/machine-id' should contain a hex string of length 32, not length 0, with no other text
  INVALID: See the manual page for dbus-uuidgen to correct this issue.

misc/docker/ubuntu-wily/Dockerfile

@@ -18,6 +18,8 @@ RUN apt-get -y update && \
             language-pack-en \
             libjs-pdf
 
+RUN dbus-uuidgen --ensure
+
 RUN useradd user && mkdir /home/user && chown -R user:users /home/user
 USER user
 WORKDIR /home/user